Question: Suppose the circumference of a circle is ${16\pi}$. What is its area?
Solution: ${c = 16\pi}$ ${K = 64\pi}$ First, find the radius: $r = c/2\pi = {16\pi}/2\pi = {8}$ Now find the area: $K = \pi r^2$, so $K = \pi \cdot {8}^2 = {64\pi}$.